GDC-0994 Fig xA a A SEM image of

Further addition of H2S to 0.3% slightly improved the peak power density to 105 mW cm−2. From that point on, there were no significant variations when H2S concentration was increased to higher levels and a plateau of peak power density had been reached. In contrast, when the balance gas was switched from H2 to Ar that is inert, the maximum power density was merely 45 mW cm−2 in 0.5% H2S + Ar.